I always thought question/answer bans were present on Stack Overflow (and maybe in all the trilogy sites). I was recently chatting with a user, and he said there are answer bans on other sites as well.

Are question/answer bans present in other sites, outside the trilogy ones? I mean, are they present in all the Stack Exchange 2.0 sites, or are they enabled in those sites that need post-bans because low quality contributions (or other reasons)?